In the late 1830s and early 1840s, Clark, a lawyer, represented a settler in a dispute with some Choctaw Native Americans over land in the Mississippi Delta.

In the late 1840s, Clark formed a plantation on the land, naming it Doe-Roe, pseudonyms commonly used in the legal profession to represent unnamed or unknown litigants (e.g., John Doe, Roe v. Wade).

The state capital of Jackson had been captured and burned by Union forces earlier that year, and most of the other strategic points in Mississippi were already overrun by US troops by the time Clark took office.

Clark's administration focused on aiding the destitute civilian population of Mississippi, officially sanctioning contraband trade with US forces in exchange for essential goods and medicine.

[4] With the collapse of the Confederacy in the spring of 1865, Clark was forcibly removed from office by the United States Army on May 22 and briefly imprisoned at Fort Pulaski near Savannah, Georgia.